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= = = Wikimedia Foundation Board of Trustees = = =
By 2003 Wikipedia had grown to 100 @,@ 000 articles in its English @-@ language version , and it became difficult for Bomis to continue financially supporting the project . With Wikipedia a drain on the company 's resources , Wales and Sanger decided to fund the project on a non @-@ profit basis . Bomis laid off most of its employees to continue operating , since Wikipedia was not generating revenue . The company owned Wikipedia from its creation through 2003 , and Wales used about $ 100 @,@ 000 of Bomis ' revenue to fund Wikipedia before the decision to shift the encyclopedia to non @-@ profit status .
In June 2003 Wikipedia was transferred to a nascent non @-@ profit organization , the Wikimedia Foundation , which was formed as a charitable institution to supervise Wikipedia and its associated wiki @-@ based sites . When the foundation was established , its staff began to solicit public funding and Bomis turned Wikipedia over to the non @-@ profit . All Bomis @-@ owned hardware used to run Wikipedia @-@ associated websites was donated to the Wikimedia Foundation , and Wales transferred Wikipedia @-@ related copyrights from Bomis to the foundation . It was first headquartered in St. Petersburg , Florida , where Bomis was located . The foundation shifted Wikipedia 's dependence away from Bomis , allowing it to purchase hardware for expansion .
The Wikimedia Foundation Board of Trustees was initially composed of Bomis ' three founders : Jimmy Wales and his two business partners , Michael Davis and Tim Shell . Shell and Davis were appointed to the board by Wales , but after Wikipedia community members complained that the board was composed of appointed individuals , the first elections were held in 2004 . Two community members , Florence <unk> and Angela Beesley , were elected to the Board of Trustees .
In August 2004 Wales was chief executive officer of Bomis , and on September 20 Wikipedia reached the million @-@ article mark on an expenditure of $ 500 @,@ 000 ( most directly from Wales ) . In November 2004 he told the St. Petersburg Times he no longer controlled Bomis ' day @-@ to @-@ day operations , but retained ownership as a shareholder . In 2005 , Tim Shell was CEO of Bomis and one of the board members overseeing Wikipedia . Shell remained CEO of Bomis in 2006 , becoming vice @-@ president of the Wikimedia Foundation and continuing to serve on its board . Bomis co @-@ founder Michael Davis became treasurer of the Wikimedia Foundation that year . Wales told The Sydney Morning Herald in 2007 that although he retained partial ownership of Bomis , " It 's pretty much dead . " According to the Internet Archive , the Bomis website was last accessible with content in 2010 ; when accessed in 2013 by the archive , it had a welcome message for <unk> .
= = Aftermath = =
In 2005 , Wales made 18 changes to his Wikipedia biography . He removed references to Bomis Babes as softcore pornography and erotica , and Larry Sanger as co @-@ founder of Wikipedia . Wales ' actions were publicized by author Rogers Cadenhead , attracting attention from US and UK media . In 2011 , Time listed Wales ' 2005 edits in its " Top 10 Wikipedia Moments " .
Wikipedia policy warned users not to edit their own biography pages , with its rules on autobiographical editing quoting Wales : " It is a social faux pas to write about yourself . " Larry Sanger said , " It does seem that Jimmy is attempting to rewrite history " , and began a discussion on the talk page of Wales ' biography about historical revisionism .
Wales called his actions fixing mistakes , but after Cadenhead publicized the edits to his biography he expressed regret for his actions . In The Times Wales said that individuals should not edit their own Wikipedia biographies , telling The New Yorker that the standard applied to himself as well . Wales warned that the activity should be discouraged because of the potential for bias : " I wish I hadn 't done it . It 's in poor taste . "
Bomis was called the " ' Playboy ' of the Internet " by The Atlantic , and the sobriquet was adopted by other media outlets . Wales considered the " ' Playboy ' of the Internet " nickname inappropriate , although he was asked in interviews if his time at Bomis made him a " porn king " . The 2010 documentary film about Wikipedia , Truth in Numbers ? , discussed this characterization of Wales by journalists . Wales , interviewed in the film , called the characterization inaccurate and explained that his company responded to content demand from customers . In later interviews , he responded to " porn king " questions by telling journalists to look at a page on Yahoo ! about pornography related to dwarfism . According to a 2007 article in Reason , " If he was a porn king , he suggests , so is the head of the biggest Web portal in the world . "
On December 14 , 2012 , academic and writer Judith Reisman stated in a piece for WorldNetDaily that in her view Wales had received revenue from a website which dealt in pornography . Relatively soon after the article was published , Wales wrote to WorldNetDaily to object to this characterization : " This is absolutely and <unk> [ sic ] false . I have never made any ' fortune ' , as a pornography trafficker or otherwise , and I have never been a ' pornography trafficker ' at all . ... I demand an immediate edit to that story to remove the lie about me . " WorldNetDaily editor Joseph Farah personally replied to Wales to explain that Wikipedia 's coverage of the history of Bomis acknowledged at the time that : " Bomis ran a website called Bomis Premium at <unk> until 2005 , offering customers access to premium , X @-@ rated pornographic content . " Wales sent an email to Farah stating Wikipedia : " doesn 't say anything remotely like me making a ' fortune ' from ' pornography . " Wales inquired to Farah what he was going to do next about what Wales characterized as " libel " . Farah responded to Wales ' reply with a subsequent email asking : " Let me get this straight : You admit making money from pornography , but you feel defamed because you didn ’ t make enough for it to be considered a ' fortune ' ? " Wales then repeated his original request to Farah and again asserted the original article was " defamatory " , writing in an email : " This is a defamatory falsehood . I have never made any ' fortune ' as a ' <unk> [ sic ] trafficker . ' Fix it . "
WorldNetDaily published a correction on December 17 , 2012 , in the form of a new full article by journalist Chelsea Schilling which presented an analysis of the history of Bomis . Schilling reported that WorldNetDaily had performed a search of archives of Bomis and found that the Bomis Premium feature had indeed advertised on its site that membership included access to naked pictures of models . Schilling 's article included historical screenshots of the appearance of the site when Bomis Premium was an active feature . She cited a Wired article , and noted the prior history from 2005 of Wales 's repeated attempts to remove references on Wikipedia to the term " pornography " in reference to Bomis . In its final determination , Schilling reported that WorldNetDaily had modified the original article from stating Wales " made his original fortune as a pornography trafficker " to : " originally made his living off a website that earned revenue from pornography traffickers " .
= = Analysis = =
The Chronicle of Philanthropy characterized Bomis as " an Internet marketing firm ... which also traded in erotic photographs for a while . " Jeff Howe wrote in his book , <unk> , about " one of Wales 's less altruistic ventures , a Web portal called Bomis.com that featured , among other items , soft @-@ core pornography . " In his book , The Future of the Internet — And How to Stop It , legal scholar Jonathan Zittrain wrote that " Bomis helped people find ' erotic photography ' , and earned money through advertising as well as subscription fees for premium content . " The Guardian described the site as on " the fringes of the adult entertainment industry " , and The Edge called Bomis.com an " explicit @-@ content search engine " . Business 2 @.@ 0 Magazine described it as " a search portal ... which created and hosted Web rings around popular search terms – including , not surprisingly , a lot of adult themes . "
= Harrie Massey =
Sir Harrie Stewart Wilson Massey FRS ( 16 May 1908 – 27 November 1983 ) was an Australian mathematical physicist who worked primarily in the fields of atomic and atmospheric physics .
A graduate of the University of Melbourne and Cambridge University , where he earned his doctorate at the Cavendish Laboratory , Massey became an independent lecturer in Mathematical Physics at the Queen 's University of Belfast in 1933 . He was appointed Goldsmid Professor of Applied Mathematics at University College London , in 1938 . During the Second World War , Massey worked at the Admiralty Research Laboratory , where he helped devise countermeasures for German magnetic naval mines , and at the Admiralty Mining Establishment in Havant , where he helped develop British naval mines . In 1943 , Mark Oliphant persuaded the Admiralty to release Massey to work on the Manhattan Project . He joined Oliphant 's British Mission at the Radiation Laboratory at the University of California , where they worked on the electromagnetic isotope separation process . When Oliphant returned to Britain in 1945 , Massey took over the Berkeley Mission .
Massey returned to University College , London , in October 1945 to find it badly damaged by bombing , and the Mathematics Department in dingy temporary accommodation . In 1950 he was appointed Quain Professor of Physics and head of the University College , London , Physics Department . The department was merged with Astronomy in 1973 , but he remained its head until he retired in 1975 . Under his direction , the Physics Department was reoriented towards particle physics and upper atmosphere physics . He worked with the Woomera Rocket Range to develop British Skylark rocket , and was on the governing board of the Anglo @-@ Australian Telescope . He was the chairman of the Committee on Space Research ( COSPAR ) from 1959 to 1978 , and of its British national chapter . He was also the first Chairman of the European Space Sciences Committee , and helped found the European Space Research Organization and the Mullard Space Science Laboratory at University College , London .
= = Early life = =
Harrie Stewart Wilson Massey was born in Invermay , Victoria , Australia , on 16 May 1908 , the only child of Harrie Stewart Massey , a miner , and his wife Eleanor Elizabeth née Wilson . He grew up in the rural community of <unk> Creek , and enrolled in the local state school in 1913 . He received his Merit Certificate , normally awarded after completing the eighth grade , when he was nine , but due to his age he still had to stay there for another three years . He won a scholarship to University High School , and moved to <unk> with his mother in 1920 . At University High School he was president of the Science Club and vice captain of the cricket team .
= = Carrier = =
At the age of 16 , Massey won a scholarship to the University of Melbourne , which he entered in 1925 . He had thoughts of studying chemistry , but was impressed by the physics lectures given by Eric <unk> . This was a stroke of luck ; first year physics lectures were normally given by Thomas Laby . Massey recalled in 1980 that " in a fairly wide experience I would rate [ Laby ] the worst lecturer I have heard " . At the University he played cricket , billiards , tennis and baseball , which he played for the University . He was awarded his Bachelor of Arts ( BSc ) in physics with first class honours in 1928 , and a Bachelor of Arts ( BA ) in mathematics in 1929 . At a meeting of the Australasian Association for the Advancement of Science in Perth in August 1925 , he met a schoolteacher , Jessica Elizabeth Bruce . They were married on 11 January 1928 at the district registrar ’ s office in Perth . They had a daughter , Pamela Lois .
At that time , the university did not offer a Doctor of Philosophy ( PhD ) program so Massey undertook a Master of Science ( MSc ) course , with both experimental and theoretical components . The former , in cooperation with Courtney Mohr , dealt with soft X @-@ ray deflection from metal surfaces ; the latter with wave mechanics . This involved translating numerous articles from German journals such as Zeitschrift für Physik , Annalen der Physik and Physikalische Zeitschrift . His external examiner was Ralph Fowler from the University of Cambridge , who was Paul Dirac 's PhD supervisor .
In 1929 , with the benefit of an Aitchison travelling scholarship from the University of Melbourne , Massey went to Trinity College , Cambridge to perform research at the Cavendish Laboratory led by Ernest Rutherford . The scholarship expired after two years , but he was awarded an 1851 Exhibition Scholarship in 1931 . At this time the Cavendish Laboratory was one of the leading centres of physics in the world . In 1932 Cavendish laboratory scientists John Cockcroft and Ernest Walton split the atomic nucleus , James Chadwick discovered the neutron , and Patrick Blackett and Giuseppe Occhialini confirmed the existence of the positron .
Fowler was appointed as Massey 's supervisor although it was clear that he did not need any supervision per se . Massey obtained his PhD on the The Collisions of Material Particles in 1932 . Shortly afterwards , he co @-@ authored a book on atomic collision processes with Nevill Mott , Theory of Atomic Collisions ( 1933 ) . He also applied the theory of collisions to models of neutron structure . At the Cavendish laboratory , he also played hockey with Cockcroft , and cricket for the Cavendish Cricket Club , becoming team captain in his final year there .
In June 1933 Massey became an independent lecturer in Mathematical Physics at the Queen 's University of Belfast . He was the only member of the department until R. A. Buckingham arrived in 1934 . Despite having to give nine lectures a week , he found time to write his second book , Negative Ions ( 1938 ) , and began working on upper atmospheric physics . Frustrated with the tiresome and time @-@ consuming process of calculation , he had his physics workshop superintendent , John Wylie , build him a small @-@ scale differential analyzer , an analog computer that could solve differential equations , for just £ 50 . This was used to solve problems related to low temperature helium , and the photo @-@ ionisation of oxygen in the upper atmosphere .
Massey was appointed Goldsmid Professor of Applied Mathematics at University College London , in 1938 , following the death of L. N. G. <unk> the previous year . He brought with him Buckingham , now an 1851 Exhibition Scholar himself , and David Bates , a promising graduate student . They brought the differential analyser with them to London , where it was destroyed by an air raid during the Second World War .
= = Second World War = =
Soon after the outbreak of war in September 1939 , the Germans began a naval mine campaign against Britain . The results were devastating . Nineteen ships totaling 59 @,@ 027 tons were sunk by mines in October , and 27 totaling 120 @,@ 958 tons in November , along with the destroyer HMS Blanche . Many more ships were damaged , including the cruiser HMS Belfast . The nature of the mines was initially unknown , but on 23 November 1939 , a bomb disposal team under Lieutenant Commander J. G. D. <unk> recovered an intact aerial mine from a mudflat at Shoeburyness , and the threat was revealed to be a magnetic mine .
In December 1939 , Massey joined a group at the Admiralty Research Laboratory in Teddington led by Stephen Butterworth . They were soon joined by a number of other physicists , including Bates , Buckingham , Francis Crick and John Gunn . Together , they came up with a series of countermeasures that enable the Navy to successfully sweep the mines . With this in hand , Massey became Deputy Chief Scientist to the Scientific Section of Mine Design Department at the Admiralty Mining Establishment in Havant in early 1941 . This time , the job was to create mines as good as the German ones . Massey brought his team with him . While Bates worked on packaging to protect the mine when it was dropped from an aircraft , Buckingham and Gunn calculated its theoretical effectiveness , and Crick designed the circuitry . Their mine codenamed MX , was soon in service , and the group turned its attention to developing acoustic or pressure mines . On the retirement of A. B. Wood in 1943 , Massey became Chief Scientist at Havant .
After the August 1943 Quebec Agreement merged the British and American atomic bomb projects , Mark Oliphant persuaded the Admiralty to release Massey to work on the Manhattan Project . In November 1943 , Massey set out with Oliphant for the Radiation Laboratory at the University of California in Berkeley in a B @-@ 24 Liberator bomber . The Radiation Laboratory 's part was to develop an electromagnetic isotope separation process . Massey was in charge of its Theoretical Group , which included American David Bohm and Australian Eric Burhop . They studied the characteristics of electric discharges in magnetic fields , today known as Bohm diffusion , and studied the ionization of uranium compounds used as feed in the electromagnetic uranium enrichment process such as uranium tetrachloride ( <unk> ) and uranium hexafluoride ( UF6 ) . Oliphant returned to Britain in March 1945 , and was replaced as head of the British mission in Berkeley by Massey . Wartime papers produced by the group were collected and published in The Characteristics of Electrical Discharges in Magnetic Fields ( 1949 ) .
= = Later life = =
Massey returned to University College , London , in October 1945 to find it badly damaged by bombing , and the Mathematics Department in dingy temporary accommodation . He was allowed to pick his own lecturers , so he chose Bats , Burhop , Buckingham and Gunn . While they had to teach mathematics , they were free to choose their own research topics , so they chose to research physics , carrying out physical experiments . This situation lasted until 1950 , when Edward Andrade retired , and Massey was appointed Quain Professor of Physics and head of the University College , London , Physics Department . The department was merged with Astronomy in 1973 , but he remained its head until he retired in 1975 . He also served as University College , London 's Vice @-@ Provost from 1969 to 1973 .
When Massey took over the Physics Department , most of his physicists , including Bates , Buckingham , Burhop and Robert Boyd , moved with him . Like the Mathematics Department , it was still in temporary accommodation owing to bomb damage during the war . A new building was under construction , but to develop the technical infrastructure , Massey hired Harry Tomlinson , who had worked for him in the British Mission in Berkeley . The Department acquired several accelerators , including a 20 MeV synchrotron from the Atomic Energy Authority . Dick Jennings and Franz Heymann built two <unk> . Under Massey , the Physics Department moved away from researching the physics of metals and liquids , and focused on particle physics and upper atmosphere physics . Massey saw the potential of computers . He arranged with Andrew Booth for a copy of his All Purpose Electronic Computer , and recruited two programmers , Joan Lawson and Jane Wallace . When the University of London established a computing unit , Buckingham left to head it .
Elected a Fellow of the Royal Society of London in 1940 , Massey was awarded its Hughes Medal in 1955 , and its Royal Medal in 1958 . He was a member of the its council from 1949 to 1951 and again from 1959 to 1960 , before serving as its Physical Secretary and Vice @-@ President from 1969 to 1978 . He became a member of the Department of Scientific and Industrial Research 's Nuclear Physics Sub @-@ Committee in 1956 . When the National Institute for Research in Nuclear Science was founded in 1957 , he became one of the initial members of its governing board . He became a member of the Research Grants Committee in 1959 , and was chairman of the Council for Scientific Policy from 1965 to 1970 . He was knighted for his services in 1960 .
Rockets had seen enormous development for military purposes during the Second World War , and Massey saw their potential for studying the upper atmosphere . He became a major supporter of space science , and wrote a book on the subject , History of British Space Science ( 1984 ) . He was the chairman of the Committee on Space Research ( COSPAR ) , which was established by the International Council of Scientific Unions , from its founding in 1959 until 1978 , and also of the British National Committee for Space Research , its British national chapter . He was also the first Chairman of the European Space Sciences Committee , and helped found the European Space Research Organization and the Mullard Space Science Laboratory at University College , London .
Space science also gave Massey an excuse to visit Australia ; he made some twenty trips . He was involved in the testing of balloons for upper atmosphere research at the University of Melbourne 's site in Mildura , Victoria . As chairman of the Rocket Subcommittee of the Royal Society 's <unk> Committee , he visited the Weapons Research Establishment near Adelaide and the Woomera Rocket Range to discuss collaboration on the British Skylark rocket , which was test fired from Woomera in 1957 . He sought to develop a UK space program in cooperation in space with Australia , the United States and European countries . He was successful in building international cooperation , although his Black Knight project was cancelled in favour of Black Arrow , which launched Prospero , only satellite launched with a British launch vehicle , from Woomera in 1971 . He was involved in the negotiations leading to the establishment of the Anglo @-@ Australian Telescope at Siding Spring Mountain in New South Wales .
Massey received an Honorary Doctorate from Heriot @-@ Watt University in 1975 .
He was a United Kingdom member and deputy chairman its governing board from 1975 to 1980 , and chairman from 1980 to 1983 .
= = Death and legacy = =
After a long illness , Massey died at his home in Esher , Surrey , which Jessica had named " Kalamunda " , from the Australian Aboriginal word for the area in Western Australia where she had once lived , on 27 November 1983 . He was survived by his wife and daughter . The Royal Society / COSPAR Massey Award is named after him , as is the Harrie Massey Lecture Theatre and Harrie Massey Prize at University College , London , and the Harrie Massey Medal and Prize , jointly awarded by the Australian Institute of Physics and British Institute of Physics . His papers are in the University College , London , archives .
= Gorgosaurus =
Gorgosaurus ( / <unk> / <unk> @-@ <unk> @-@ SOR @-@ əs ; meaning " dreadful lizard " ) is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period , between about 76 @.@ 6 and 75 @.@ 1 million years ago . Fossil remains have been found in the Canadian province of Alberta and possibly the U.S. state of Montana . Paleontologists recognize only the type species , G. libratus , although other species have been erroneously referred to the genus .
Like most known tyrannosaurids , Gorgosaurus was a bipedal predator weighing more than two metric tons as an adult ; dozens of large , sharp teeth lined its jaws , while its two @-@ fingered forelimbs were comparatively small . Gorgosaurus was most closely related to Albertosaurus , and more distantly related to the larger Tyrannosaurus . Gorgosaurus and Albertosaurus are extremely similar , distinguished mainly by subtle differences in the teeth and skull bones . Some experts consider G. libratus to be a species of Albertosaurus ; this would make Gorgosaurus a junior synonym of that genus .
Gorgosaurus lived in a lush floodplain environment along the edge of an inland sea . It was an apex predator , preying upon abundant ceratopsids and hadrosaurs . In some areas , Gorgosaurus coexisted with another tyrannosaurid , Daspletosaurus . Although these animals were roughly the same size , there is some evidence of niche differentiation between the two . Gorgosaurus is the best @-@ represented tyrannosaurid in the fossil record , known from dozens of specimens . These plentiful remains have allowed scientists to investigate its ontogeny , life history and other aspects of its biology .
= = Description = =
Gorgosaurus was smaller than Tyrannosaurus or Tarbosaurus , closer in size to Albertosaurus and Daspletosaurus . Adults reached 8 to 9 m ( 26 to 30 ft ) from snout to tail . Paleontologists have estimated full @-@ grown adults to weigh about 2 @.@ 5 tonnes ( 2 @.@ 8 short tons ) , perhaps approaching 2 @.@ 8 tonnes ( 3 @.@ 1 short tons ) . The largest known skull measures 99 cm ( 39 in ) long , just slightly smaller than that of Daspletosaurus . As in other tyrannosaurids , the skull was large compared to its body size , although chambers within the skull bones and large openings ( fenestrae ) between bones reduced its weight . Albertosaurus and Gorgosaurus share proportionally longer and lower skulls than Daspletosaurus and other tyrannosaurids . The end of the snout was blunt , and the nasal and parietal bones were fused along the midline of the skull , as in all other members of the family . The eye socket was circular rather than oval or keyhole @-@ shaped as in other tyrannosaurid genera . A tall crest rose from the lacrimal bone in front of each eye , similar to Albertosaurus and Daspletosaurus . Differences in the shape of bones surrounding the brain set Gorgosaurus apart from Albertosaurus .
Gorgosaurus teeth were typical of all known tyrannosaurids . The eight premaxillary teeth at the front of the snout were smaller than the rest , closely packed and D @-@ shaped in cross section . In Gorgosaurus , the first tooth in the maxilla was also shaped like the premaxillary teeth . The rest of the teeth were oval in cross section , rather than blade @-@ like as in most other theropods . Along with the eight premaxillary teeth , Gorgosaurus had 26 to 30 maxillary teeth and 30 to 34 teeth in the dentary bones of the lower jaw . This number of teeth is similar to Albertosaurus and Daspletosaurus but is fewer than those of Tarbosaurus or Tyrannosaurus .
Gorgosaurus shared its general body plan with all other tyrannosaurids . Its massive head was perched on the end of an S @-@ shaped neck . In contrast to its large head , its forelimbs were very small . The forelimbs had only two digits , although a third metacarpal is known in some specimens , the vestigial remains of the third digit seen in other theropods . Gorgosaurus had four digits on each hindlimb , including a small first toe ( hallux ) which did not contact the ground . Tyrannosaurid hindlimbs were long relative to overall body size compared with other theropods . The largest known Gorgosaurus femur measured 105 cm ( 41 in ) long . In several smaller specimens of Gorgosaurus , the tibia was longer than the femur , a proportion typical of fast @-@ running animals . The two bones were of equal length in the largest specimens . The long , heavy tail served as a counterweight to the head and torso and placed the center of gravity over the hips .
In 2001 , paleontologist Phil Currie reported skin impressions from the holotype specimen of G. libratus . He originally reported the skin as being essentially smooth and lacking the scales found in other dinosaurs , similar to the secondarily featherless skin found in large modern birds . Scales of some sort were present in this specimen , but they are reportedly widely dispersed from each other and very small . Other patches of isolated Gorgosaurus skin shows denser , and larger though still relatively fine scales ( smaller than hadrosaurid scales and approximately as fine as a Gila monster 's ) . Neither of these specimens was associated with any particular bone or specific body area . In the Encyclopedia of Dinosaurs Kenneth Carpenter pointed out that traces of skin impressions from the tail of Gorgosaurus showed similar small rounded or hexagonal scales .
= = Classification and systematics = =
Gorgosaurus is classified in the theropod subfamily Albertosaurinae within the family Tyrannosauridae . It is most closely related to the slightly younger Albertosaurus . These are the only two definite albertosaurine genera that have been described , although other undescribed species may exist . Appalachiosaurus was described as a basal tyrannosauroid just outside Tyrannosauridae , although American paleontologist Thomas Holtz published a phylogenetic analysis in 2004 which indicated it was an albertosaurine . More recent , unpublished work by Holtz agrees with the original assessment . All other tyrannosaurid genera , including Daspletosaurus , Tarbosaurus and Tyrannosaurus , are classified in the subfamily Tyrannosaurinae . Compared to the tyrannosaurines , albertosaurines had slender builds , with proportionately smaller , lower skulls and longer bones of the lower leg ( tibia ) and feet ( metatarsals and phalanges ) .
The close similarities between Gorgosaurus libratus and Albertosaurus sarcophagus have led many experts to combine them into one genus over the years . Albertosaurus was named first , so by convention it is given priority over the name Gorgosaurus , which is sometimes considered its junior synonym . William Diller Matthew and Barnum Brown doubted the distinction of the two genera as early as 1922 . Gorgosaurus libratus was formally reassigned to Albertosaurus ( as Albertosaurus libratus ) by Dale Russell in 1970 , and many subsequent authors followed his lead . Combining the two greatly expands the geographical and chronological range of the genus Albertosaurus . Other experts maintain the two genera as separate . Canadian paleontologist Phil Currie claims there are as many anatomical differences between Albertosaurus and Gorgosaurus as there are between Daspletosaurus and Tyrannosaurus , which are almost always kept separate . He also notes that undescribed tyrannosaurids discovered in Alaska , New Mexico and elsewhere in North America may help clarify the situation . Gregory S. Paul has suggested that Gorgosaurus libratus is ancestral to Albertosaurus sarcophagus .
Below is the cladogram of Tyrannosauridae based on the phylogenetic analysis conducted by Loewen et al. in 2013 .
= = Discovery and naming = =
Gorgosaurus libratus was first described by Lawrence Lambe in 1914 . Its name is derived from the Greek <unk> / <unk> ( " fierce " or " terrible " ) and σαυρος / saurus ( " lizard " ) . The type species is G. libratus ; the specific epithet " balanced " is the past participle of the Latin verb <unk> , meaning " to balance " .
The holotype of Gorgosaurus libratus ( NMC 2120 ) is a nearly complete skeleton associated with a skull , discovered in 1913 by Charles M. Sternberg . This specimen was the first tyrannosaurid found with a complete hand . It was found in the Dinosaur Park Formation of Alberta and is housed in the Canadian Museum of Nature in Ottawa . Prospectors from the American Museum of Natural History in New York City were active along the Red Deer River in Alberta at the same time , collecting hundreds of spectacular dinosaur specimens , including four complete G. libratus skulls , three of which were associated with skeletons . Matthew and Brown described four of these specimens in 1923 .
Matthew and Brown also described a fifth skeleton ( AMNH <unk> ) , which Charles H. Sternberg had collected in 1917 and sold to their museum . It was smaller than other Gorgosaurus specimens , with a lower , lighter skull and more elongate limb proportions . Many sutures between bones were unfused in this specimen as well . Matthew and Brown noted that these features were characteristic of juvenile tyrannosaurids , but still described it as the holotype of a new species , G. sternbergi . Today 's paleontologists regard this specimen as a juvenile G. libratus . Dozens of other specimens have been excavated from the Dinosaur Park Formation and are housed in museums across the United States and Canada . G. libratus is the best @-@ represented tyrannosaurid in the fossil record , known from a virtually complete growth series .
In 1856 , Joseph Leidy described two tyrannosaurid premaxillary teeth from Montana . Although there was no indication of what the animal looked like , the teeth were large and robust , and Leidy gave them the name Deinodon . Matthew and Brown commented in 1922 that these teeth were indistinguishable from those of Gorgosaurus , but in the absence of skeletal remains of Deinodon , opted not to unequivocally <unk> the two genera , provisionally naming a ? Deinodon libratus . Although Deinodon teeth are very similar to those of Gorgosaurus , tyrannosaurid teeth are extremely uniform , so it cannot be said for certain which animal they belonged to . Deinodon is usually regarded as a nomen dubium today . Additional likely synonyms of G. libratus and / or D. horridus include Laelaps <unk> , Laelaps <unk> , Laelaps incrassatus , and Dryptosaurus <unk> .
Several tyrannosaurid skeletons from the Two Medicine Formation and Judith River Formation of Montana probably belong to Gorgosaurus , although it remains uncertain whether they belong to G. libratus or a new species . One specimen from Montana ( <unk> 2001 @.@ 89 @.@ 1 ) , housed in the Children 's Museum of Indianapolis , shows evidence of severe pathologies , including healed leg , rib , and vertebral fractures , osteomyelitis ( infection ) at the tip of the lower jaw resulting in permanent tooth loss , and possibly a brain tumor .
= = = <unk> species = = =
Several species were incorrectly assigned to Gorgosaurus in the twentieth century . A complete skull of a small tyrannosaurid ( <unk> <unk> ) , found in the younger , late Maastrichtian @-@ age Hell Creek Formation of Montana , was named Gorgosaurus lancensis by Charles Whitney Gilmore in 1946 . This specimen was renamed Nanotyrannus by Bob Bakker and colleagues in 1988 . Currently , many paleontologists regard Nanotyrannus as a juvenile Tyrannosaurus rex . Similarly , Evgeny Maleev created the names Gorgosaurus lancinator and Gorgosaurus novojilovi for two small tyrannosaurid specimens ( PIN 553 @-@ 1 and PIN 552 @-@ 2 ) from the Nemegt Formation of Mongolia in 1955 . Kenneth Carpenter renamed the smaller specimen Maleevosaurus novojilovi in 1992 , but both are now considered juveniles of Tarbosaurus bataar .
= = Paleobiology = =
= = = Coexistence with Daspletosaurus = = =
In the middle stages of the Dinosaur Park Formation , Gorgosaurus lived alongside a rarer species of the tyrannosaurine , Daspletosaurus . This is one of the few examples of two tyrannosaur genera coexisting . Similar @-@ sized predators in modern predator guilds are separated into different ecological niches by anatomical , behavioral or geographical differences that limit competition . Niche differentiation between the Dinosaur Park tyrannosaurids is not well understood . In 1970 , Dale Russell hypothesized that the more common Gorgosaurus actively hunted fleet @-@ footed hadrosaurs , while the rarer and more troublesome ceratopsians and ankylosaurians ( horned and heavily armoured dinosaurs ) were left to the more heavy built Daspletosaurus . However , a specimen of Daspletosaurus ( OTM 200 ) from the contemporaneous Two Medicine Formation of Montana preserves the digested remains of a juvenile hadrosaur in its gut region , and another bonebed contains the remains of three Daspletosaurus along with the remains of at least five hadrosaurs .
Unlike some other groups of dinosaurs , neither genus was more common at higher or lower elevations than the other . However , Gorgosaurus appears more common in northern formations like Dinosaur Park , with species of Daspletosaurus being more abundant to the south . The same pattern is seen in other groups of dinosaurs . Chasmosaurine ceratopsians and hadrosaurine hadrosaurs are also more common in the Two Medicine Formation of Montana and in southwestern North America during the Campanian , while centrosaurine and lambeosaurines dominate in northern latitudes . Holtz has suggested this pattern indicates shared ecological preferences between tyrannosaurines , chasmosaurines and hadrosaurines . At the end of the later Maastrichtian stage , tyrannosaurines like Tyrannosaurus rex , hadrosaurines like Edmontosaurus and Kritosaurus and chasmosaurines like Triceratops and Torosaurus were widespread throughout western North America , while lambeosaurines were rare , consisting of a few species like Hypacrosaurus , and albertosaurines and centrosaurines had gone extinct ; however , they had thrived in Asia with species like Sinoceratops and Alioramus .